Regarding Three, one of the telco available in the UK, as the parent said they were already aligned with this proposition with their "Feel at home" option.
Since it covers the EU and many other non EU countries (USA included for instance) I think it'll stay this way.
The 3 Feel at Home offer was (and is, for non-EU destinations) an extra, paid add-on to the basic "essentials" service. You also get tethering on that higher price plan, so maybe the average HN user wouldn't consider the lower tier and just counts it as 'free' from their perspective.
Since it covers the EU and many other non EU countries (USA included for instance) I think it'll stay this way.